In automobiles or automotive vehicles, a power source is connected to a vehicle body via a torque arm. The torque arm includes a first bush connected to the vehicle body, a second bush connected to the power source, and a connection section interconnecting the first bush and the second bush.
In the first bush, a first inner tube is disposed within and coaxially with a first outer tube, and a first rubber-made elastic member is disposed in a first space between the first outer tube and the first inner tube. In the second bush, a second inner tube is disposed within and coaxially with a second outer tube, and a second rubber-made elastic member is disposed in a second space between the second outer tube and the second inner tube. The first outer tube of the first bush and the second outer tube of the second bush are interconnected to constitute the torque arm.
Among the conventionally-known torque arms is one in which the first and second outer tubes and the connection section are each divided into two halves to provide a pair of half members (see, for example, Patent Literature 1). In manufacturing such a torque arm, first, the pair of half members are superposed on each other to form the first and second outer tubes and the connection section. Then, with the pair of half members superposed on each other, the first inner tube is positioned within the first outer tube, and the second inner tube is positioned within the second outer tube.
Then, the pair of half members superposed on each other and the first and second inner tubes are inserted into a cavity of a mold. Then, a rubber material is filled into the cavity, and the filled rubber material is molded through vulcanization (i.e., molded by cross-linking). Then, with the vulcanization-molded rubber, a first rubber-made elastic member is formed in the first space to provide the first bush, while a second rubber-made elastic member is formed in the second space to provide the second bush. Simultaneously, the pair of half members are bonded to each other by the vulcanized rubber. In this manner, vulcanization-molding of the torque arm is completed.